Communication method and apparatus

ABSTRACT

Embodiments of this disclosure provide a communication method and apparatus, to reduce a waiting delay during transmission of retransmitted data and out-of-order data. In this method, a user plane function network element may receive first data and second data, determines, based on first information, that the second data is retransmitted data of the first data, and sends indication information to an access network network element. The indication information herein may indicate that the second data is the retransmitted data, or indicate a sending priority of the second data. Based on this solution, the access network network element may send the first data and the second data based on the indication information, and may preferentially send the retransmitted data to reduce the waiting delay during data transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

This disclosure is a continuation of International Patent ApplicationNo. PCT/CN2021/119960, filed on Sep. 23, 2021, which claims priority toChinese Patent Application No. 202011042985.6, filed on Sep. 28, 2020.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

This disclosure relates to the field of wireless communicationtechnologies, and in particular, to a communication method andapparatus.

BACKGROUND

Rapid development of the new media industry leads to a sharp increase ofdata volume in the media industry, and this poses a challenge to anetwork transmission capability. For example, emerging media such asultra-high-definition video and virtual reality (virtual reality,VR)/augmented reality (augmented reality, AR) panoramic video have highrequirements on image quality and a delay, and a large amount of datamay be transmitted in real time. Currently, the transmission controlprotocol (transmission control protocol, TCP) is reliable, and thereforeis widely used for network transmission.

However, due to in-sequence delivery of TCP, an application layerobtains and parses data of a subsequent sequence number only after adata packet of a previous sequence number arrives. When data isretransmitted due to packet loss, data packets may be out of order. Theout-of-order data packets may cause a client to wait during datatransmission. This increases a waiting delay, and frame freezing duringplay is caused at a media service layer.

SUMMARY

This disclosure provides a communication method and apparatus, to reducea waiting latency during transmission of retransmitted data andout-of-order data.

According to a first aspect, a communication method is provided. Themethod may be performed by a user plane function network element in anembodiment of this disclosure, or by a chip similar to the user planefunction network element. In this method, the user plane functionnetwork element may receive first data and second data. The user planefunction network element may determine, based on first information, thatthe second data is retransmitted data of the first data. The user planefunction network element may send indication information to an accessnetwork network element. The indication information herein may indicatethat the second data is the retransmitted data, or indicate a sendingpriority of the second data.

Based on this solution, the user plane function network element maydetermine, based on the first information, that the second data is theretransmitted data of the first data, and send the indicationinformation to the access network network element. In this way, theaccess network network element may send the first data and the seconddata based on the indication information, and may preferentially sendthe retransmitted data to reduce a waiting delay during datatransmission.

In a possible implementation, the user plane function network elementmay receive the first information from an application server. The firstinformation may include a data packet sequence number differencethreshold. For example, the first information may include a TCP sequencenumber difference threshold.

Based on this solution, the user plane function network element maydetermine, based on a data packet sequence number of the second data andthe data packet sequence number difference threshold included in thefirst information, that the second data is the retransmitted data of thefirst data, and send the indication information to the access networknetwork element, to reduce the data transmission delay.

In a possible implementation, the user plane function network elementmay determine that a difference between a data packet sequence number ofthe second data and a data packet sequence number of adjacent dataexceeds the foregoing data packet sequence number difference threshold.In other words, when the difference between the data packet sequencenumber of the second data and the data packet sequence number of theadjacent data exceeds the data packet difference threshold, it may bedetermined that the second data is the retransmitted data of the firstdata. The data packet difference threshold may be set based on anempirical value. This is not specifically limited in this disclosure.

Based on this solution, the user plane function network element mayidentify the retransmitted data based on the difference between the datapacket sequence number of the second data and the data packet sequencenumber of the adjacent data, so that the retransmitted data packet canbe preferentially transmitted.

In a possible implementation, the user plane function network elementmay receive the first information from the access network networkelement. The first information may indicate a receiving response to thefirst data.

Based on this solution, after the user plane function network elementsends the first data to the access network network element, and whenreceiving the receiving response from the access network networkelement, the user plane function network element may determine that thefirst data has been received and retransmission does not need to betriggered.

In a possible implementation, the user plane function network elementmay determine that the first information does not include the receivingresponse to the first data. For example, if the user plane functionnetwork element determines that a data packet sequence number of thesecond data is the same as that of the first data, and no receivingresponse to the first data is received, the user plane function networkelement may determine that the second data is the retransmitted data ofthe first data.

Based on this solution, the user plane function network element mayidentify the retransmitted data based on the receiving response to thefirst data, and may indicate, based on the indication information, theaccess network network element to perform priority scheduling, andpreferentially transmit the retransmitted data.

In a possible implementation, the indication information may beidentification information of a first quality of service (quality ofservice, QoS) flow. The first data may be sent through a second QoSflow, and a priority of the first QoS flow may be higher than that ofthe second QoS flow.

Based on this solution, the user plane function network element mayindicate, based on the identification information of the QoS flow, thatthe second data is transmitted through the first QoS flow with a higherpriority, to preferentially transmit the retransmitted data.

According to a second aspect, a communication method is provided. Themethod may be performed by an access network network element inembodiments of this disclosure, or by a chip whose function is similarto a function of the access network network element. In this method, theaccess network network element may receive first data and second data.The access network network element may receive indication informationfrom a user plane function network element. The indication informationmay indicate that the second data is retransmitted data of the firstdata, and the access network network element may determine a sendingpriority of the second data based on the indication information.

Based on this solution, the access network network element may determinethe sending priority of the second data based on the indicationinformation from the user plane function network element, to performpriority scheduling, and transmit the first data and the second data.

In a possible implementation, the access network network element maydetermine, based on the indication information, that the sendingpriority of the second data is higher than that of the first data.

Based on this solution, the access network network element maydetermine, based on the indication information, that the sendingpriority of the second data is higher, so that priority scheduling isperformed to preferentially transmit the second data, thereby reducing awaiting delay during data transmission.

In a possible implementation, the access network network element mayreceive second information from a session management function networkelement. The second information herein may include indicationinformation. In this way, when the indication information from the userplane function network element is the same as the indication informationfrom the session management function network element, the access networknetwork element may determine that the second data is the retransmitteddata of the first data.

Based on this solution, the access network network element maydetermine, based on the indication information from the sessionmanagement function network element and the indication information fromthe user plane function network element, that the second data is theretransmitted data of the first data, so that priority scheduling isperformed to preferentially transmit the retransmitted data, therebyreducing the waiting delay of data transmission.

In a possible implementation, the indication information may beidentification information of a first QoS flow, the first data may bereceived through a second QoS flow, and a priority of the first QoS flowis higher than that of the second QoS flow.

Based on this solution, the access network network element may implementpriority scheduling through the first QoS flow and the second QoS flowwith different priorities, and may transmit the second data through thefirst QoS flow, to reduce a transmission delay of the retransmitteddata.

According to a third aspect, a communication method is provided. Themethod may be performed by a policy control function network element inembodiments of this disclosure, or by a chip whose function is similarto a function of the policy control function network element. In thismethod, the policy control function network element may receiveindication information from an application server. The policy controlfunction network element may generate a first QoS flow and a second QoSflow based on the indication information, where the second QoS flow maybe for sending first data, and the first QoS flow may be for sendingsecond data. The second data herein may be retransmitted data of thefirst data. The policy control function network element may send policyinformation of the first QoS flow and policy information of the secondQoS flow to a session management function network element, and thepolicy information herein may indicate that a priority of the first QoSflow is higher than that of the second QoS flow.

Based on this solution, the policy control function network element maygenerate the first QoS flow and the second QoS flow with differentpriorities based on the indication information, to transmit the firstdata and the second data through the QoS flows with differentpriorities, thereby implementing priority scheduling and reducing a datatransmission delay.

According to a fourth aspect, a communication method is provided. Themethod may be performed by an access network network element inembodiments of this disclosure, or by a chip whose function is similarto a function of the access network network element. In this method, theaccess network network element may receive first data. The first dataherein may include first indication information, and the firstindication information may indicate a sending sequence of data packetsof the first data at an application server end. The access networknetwork element may determine a sending priority of the first data basedon the first indication information.

Based on this solution, the access network network element maydetermine, based on the sending sequence of the data packets of thefirst data at the application server end, the sending priority of thefirst data, to perform priority scheduling and send the first data atdifferent priorities, thereby reducing a data transmission delay.

In a possible implementation, the access network network element mayreceive second indication information from a session management functionnetwork element. The second indication information herein may indicatethe access network network element to transmit data based on priorityinformation.

Based on this solution, the access network network element may performpriority scheduling based on the second indication information, and sendthe first data in a priority order of the first data.

According to a fifth aspect, a communication method is provided. Themethod may be performed by an application server, or by a chip whosefunction is similar to a function of the application server. In themethod, the application server may send first data to an access networknetwork element through a user plane function network element. The firstdata herein may include first indication information. The firstindication information herein may be a sending sequence of data packetsof the first data at an application server end, and the first indicationinformation may be for determining a sending priority of the first data.

Based on this method, the application server may indicate the sendingpriority of the first data to the access network network element basedon the first indication information, so that the access network networkelement performs priority scheduling, and sends the first data in apriority order of the first data, thereby reducing a data transmissiondelay.

According to a sixth aspect, a communication apparatus is provided. Thecommunication apparatus may include modules/units configured to performthe first aspect or any one of the possible implementations of the firstaspect, or may further include modules/units configured to perform thesecond aspect or any one of the possible implementations of the secondaspect, or may further include modules/units configured to perform thethird aspect or any one of the possible implementations of the thirdaspect, or may further include modules/units configured to perform thefourth aspect or any one of the possible implementations of the fourthaspect, or may further include modules/units configured to perform thefifth aspect or any one of the possible implementations of the fifthaspect. For example, a communication unit and a processing unit.

According to a seventh aspect, a communication apparatus is provided,and the communication apparatus includes a processor and a memory. Thememory is configured to store computer executable instructions. When acontroller runs, the processor performs the computer executableinstructions in the memory, to utilize a hardware resource in thecontroller to perform a step of the method in the first aspect or anyone of the possible implementations of the first aspect, or perform astep of the method in the second aspect or any one of the possibleimplementations of the second aspect, or perform a step of the method inthe third aspect or any one of the possible implementations of the thirdaspect, or perform a step of the method in the fourth aspect or any oneof the possible implementations of the fourth aspect, or perform a stepof the method in the fifth aspect or any one of the possibleimplementations of the fifth aspect.

According to an eighth aspect, this disclosure provides acomputer-readable storage medium. The computer-readable storage mediumstores instructions. When the instructions are run on a computer, thecomputer is enabled to perform the methods in the foregoing aspects.

According to a ninth aspect, this disclosure provides a computer programproduct that stores instructions. When the computer program product isrun on a computer, the computer is enabled to perform the methods in theforegoing aspects.

In addition, for beneficial effects of the sixth aspect to the ninthaspect, refer to the beneficial effects shown in the first aspect to thefifth aspect, and details are not described herein again.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a communication system according to an embodiment of thisdisclosure;

FIG. 2 is one of schematic structural diagrams of an access networkdevice according to an embodiment of this disclosure;

FIG. 3 is one of schematic structural diagrams of an access networkdevice according to an embodiment of this disclosure;

FIG. 4 is one of schematic structural diagrams of an access networkdevice according to an embodiment of this disclosure;

FIG. 5 is a schematic diagram of an application scenario according to anembodiment of this disclosure;

FIG. 6 is one of example flowcharts of a communication method accordingto an embodiment of this disclosure;

FIG. 7 is one of example flowcharts of a communication method accordingto an embodiment of this disclosure;

FIG. 8 is one of example flowcharts of a communication method accordingto an embodiment of this disclosure;

FIG. 9A and FIG. 9B are one of example flowcharts of a communicationmethod according to an embodiment of this disclosure;

FIG. 10 is one of example flowcharts of a communication method accordingto an embodiment of this disclosure;

FIG. 11 is one of example flowcharts of a communication method accordingto an embodiment of this disclosure;

FIG. 12 is a schematic diagram of an apparatus with a communicationfunction according to an embodiment of this disclosure; and

FIG. 13 is a block diagram of an apparatus with a communication functionaccording to an embodiment of this disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes some terms in embodiments of this disclosure, tofacilitate understanding of a person skilled in the art.

(1) Retransmitted data refers to data in retransmission of data sent bya device. The retransmitted data may be the same as data in the firsttransmission, or may be in a different redundancy version of the data inthe first transmission.

(2) The terms “system” and “network” may be used interchangeably inembodiments of this disclosure. “A plurality of” means two or more, andother quantifiers are similar to this. “And/or” describes an associationrelationship between associated objects and indicates that threerelationships may exist. For example, A and/or B may indicate thefollowing three cases: Only A exists, both A and B exist, and only Bexists. In addition, an element (element) that appears in singular forms“a”, “an”, and “the” does not mean “one or only one” unless otherwisespecified in the context, but means “one or more”. For example, “adevice” means one or more such devices. Further, “at least one of (atleast one of) . . . ” means one or any combination of subsequentassociated objects. For example, “at least one of A, B, and C” includesA, B, C, AB, AC, BC, or ABC.

For an architecture of a possible communication system to which thecommunication method provided in this embodiment of this disclosure isapplicable, the architecture of the communication system may include anetwork exposure function network element, a policy control functionnetwork element, a data management network element, an applicationfunction network element, an access and mobility management functionnetwork element, a session management function network element, aterminal device, an access network device, a user plane function networkelement, and a data network. FIG. 1 shows a possible example of anarchitecture of the communication system, and specifically includes: anetwork exposure function (network exposure function, NEF) networkelement, a policy control function (policy control function, PCF)network element, a data management (unified data management, UDM)network element, an application function (application function, AF)network element, an AMF network element, a session management function(session management function, SMF) network element, UE, an accessnetwork (access network, AN) device, a user plane function (user planefunction, UPF) network element, and a data network (data network, DN).The AMF network element may be connected to the terminal device throughan N1 interface, the AMF may be connected to the AN device through an N2interface, the AN device may be connected to the UPF through an N3interface, the SMF may be connected to the UPF through an N4 interface,and the UPF may be connected to the DN through an N6 interface. Aninterface name is merely an example for description. This is notspecifically limited in this embodiment of this disclosure. It should beunderstood that this embodiment of this disclosure is not limited to thecommunication system shown in FIG. 1 . Names of the network elementsshown in FIG. 1 are merely used as examples for description herein, anddo not constitute limitations on the network elements included in thearchitecture of the communication system to which the method in thisdisclosure is applicable. The following describes in detail functions ofeach network element or device in the communication system.

The terminal device may also be referred to as user equipment (userequipment, UE), a mobile station (mobile station, MS), a mobile terminal(mobile terminal, MT), or the like, and is a device that provides voiceand/or data connectivity for a user. For example, the terminal devicemay include a handheld device, a vehicle-mounted device, and the likethat has a wireless connection function. Currently, the terminal devicemay be a mobile phone (mobile phone), a tablet computer, a notebookcomputer, a palmtop computer, a mobile Internet device (mobile internetdevice, MID), a wearable device, a virtual reality (virtual reality, VR)device, an augmented reality (augmented reality, AR) device, a wirelessterminal in industrial control (industrial control), a wireless terminalin self-driving (self-driving), a wireless terminal in remote medicalsurgery (remote medical surgery), a wireless terminal in a smart grid(smart grid), a wireless terminal in transportation safety(transportation safety), a wireless terminal in a smart city (smartcity), a wireless terminal in a smart home (smart home), or the like. InFIG. 2 , the terminal device is shown as UE. This is merely used as anexample, and poses no limitation on the terminal device.

A radio access network may be the access network (access network, AN)shown in FIG. 1 and provide a wireless access service for the terminaldevice. The access network device is a device, in the communicationsystem, that enables the terminal device to access a wireless network.The access network device is a node in the radio access network, and mayalso be referred to as a base station, or may also be referred to as aradio access network (radio access network, RAN) node (or device).Currently, for example, the access network device is a gNB, atransmission reception point (transmission reception point, TRP), anevolved NodeB (evolved NodeB, eNB), a radio network controller (radionetwork controller, RNC), a NodeB (NodeB, NB), a base station controller(base station controller, BSC), a base transceiver station (basetransceiver station, BTS), a home base station (for example, a homeevolved NodeB or a home NodeB, HNB), a baseband unit (baseband unit,BBU), or a wireless fidelity (wireless fidelity, Wi-Fi) access point(access point, AP).

For example, the radio access network device in embodiments of thisdisclosure may be divided into two parts based on a protocol stackfunction: a central unit (central unit, CU) and a distributed unit(distributed unit, DU). As shown in FIG. 2 , one radio access networkdevice may include one CU and at least one DU. The CU is connected tothe at least one DU, and may be configured to manage or control the atleast one DU. In this structure, protocol layers of the radio accessnetwork device in the communication system may be separated. Someprotocol layer functions are implemented in the CU, and functions ofsome or all of remaining protocol layers are distributed in the DU, andthe CU centrally controls the DU. For example, the radio access networkdevice is a gNB. Protocol layers of the gNB include a radio resourcecontrol (radio resource control, RRC) layer, a service data adaptationprotocol (service data adaptation protocol, SDAP) layer, a packet dataconvergence protocol (packet data convergence protocol, PDCP) layer, aradio link control (radio link control, RLC) layer, a media accesscontrol (media access control, MAC) layer, and a physical layer. Forexample, the CU may be configured to implement functions of the RRClayer, the SDAP layer, and the PDCP layer, and the DU may be configuredto implement functions of the RLC layer, the MAC layer, and the physicallayer. Protocol stacks included in the CU and the DU are notspecifically limited in embodiments of this disclosure. As shown in FIG.3 , the CU may be connected to the DU through an F1 interface, the CU isconnected to another radio access network device through an Xninterface, and the CU is connected to a 5G core network (5G Core, 5GC)through an NG interface.

For example, the CU in embodiments of this disclosure may be furtherdivided into one control plane (CU-control plane, CU-CP) network elementand at least one user plane (CU-user plane, CU-UP) network element. TheCU-CP may be for control plane management, and the CU-UP may be for userplane data transmission. An interface between the CU-CP and the CU-UPmay be an El interface. An interface between the CU-CP and the DU may bea F1-C, and is for control plane signaling transmission. An interfacebetween the CU-UP and the DU may be a F1-U, and is for user plane datatransmission. An interface connecting the CU-UPs may be an Xn-Uinterface, to perform user plane data transmission. For example, the gNBis used as an example. A structure of the gNB may be shown in FIG. 4 .

The data network such as the data network (data network, DN) shown inFIG. 1 may be the Internet (Internet), an IP multimedia service (IPMultimedia Service, IMS) network, a regional network (namely, a localnetwork, such as a mobile edge computing (mobile edge computing, MEC)network), or the like. The data network includes an application server,and the application server provides a service for the terminal device bytransmitting data with the terminal device.

The core network is for enabling the terminal device to access the DNthat can implement a service of the terminal device. The followingdescribes functions of network elements in the core network.

The access and mobility management function network element may beconfigured to manage access control and mobility of the terminal device.In a practical application, the network element includes a mobilitymanagement function of a mobility management entity (mobility managemententity, MME) in a network framework in long term evolution (long termevolution, LTE), and further includes an access management function, andmay be specifically responsible for registration, mobility management,tracking area update procedure, reachability detection, selection of asession management function network element, mobility state transitionmanagement, and the like of the terminal device. For example, in 5G, theaccess and mobility management function network element may be an AMF(access and mobility management function) network element, as shown inFIG. 1 . In future communication, for example, in 6G, the access andmobility management function network element may still be an AMF networkelement or have another name. This is not limited in this disclosure.When the access and mobility management function network element is anAMF network element, the AMF may provide a Namf service.

The session management function network element may be configured to beresponsible for session management (including session establishment,modification, and release) of the terminal device, selection andreselection of the user plane function network element, internetprotocol (internet protocol, IP) address assignment of the terminaldevice, quality of service (quality of service, QoS) control, and thelike. For example, in 5G, the session management function networkelement may be an SMF (session management function) network element, asshown in FIG. 1 . In future communication, for example, in 6G, thesession management function network element may still be an SMF networkelement or have another name. This is not limited in this disclosure.When the session management function network element is an SMF networkelement, the SMF may provide a Nsmf service.

The policy control function network element may be responsible forpolicy control decision making, and providing functions such asdetection of a service-based data flow and an application, gating, QoS,and flow-based charging control. For example, in 5G, the policy controlfunction network element may be a PCF (policy control function) networkelement, as shown in FIG. 1 . In future communication, for example, in6G, the policy control function network element may still be a PCFnetwork element or have another name. This is not limited in thisdisclosure. When the policy control function network element is a PCFnetwork element, the PCF network element may provide an Npcf service.

A main function of the application function network element is tointeract with a 3rd generation partnership project (the 3rd generationpartnership project, 3GPP) core network to provide a service, to affectservice flow routing, access network capability exposure, policycontrol, and the like. For example, in 5G, the application functionnetwork element may be an AF network element, as shown in FIG. 1 . Infuture communication, for example, in 6G, the application functionnetwork element may still be an AF network element or have another name.This is not limited in this disclosure. When the application functionnetwork element is an AF network element, the AF network element mayprovide a Naf service.

The data management network element may be configured to managesubscription data of the terminal device, registration informationrelated to the terminal device, and the like. For example, in 5G, thedata management network element may be a unified data management networkelement (unified data management, UDM), as shown in FIG. 1 . In futurecommunication, for example, in 6G, the data management network elementmay still be a UDM network element or have another name. This is notlimited in this disclosure. When the data management network element isa UDM network element, the UDM network element may provide a Nudmservice.

The network exposure function network element may be configured toenable 3GPP to securely provide a network service capability for athird-party AF (for example, a service capability server (ServicesCapability Server, SCS) or an application server (Application Server,AS)). For example, in 5G, the network exposure function network elementmay be an NEF, as shown in FIG. 1 . In future communication, forexample, in 6G, the network exposure function network element may stillbe an NEF network element or have another name. This is not limited inthis disclosure. When the network exposure function network element isan NEF, the NEF may provide an Nnef service for other network functionnetwork elements.

Each of the foregoing network elements in the core network may also bereferred to as a functional entity, and may be a network elementimplemented on dedicated hardware, or may be a software instance runningon dedicated hardware, or an instance of a virtualization function on anappropriate platform. For example, the virtualization platform may be acloud platform.

It should be noted that the communication system architecture shown inFIG. 1 is not limited to including only the network elements shown inthe figure, and may further include other devices not shown in thefigure. Details are not described herein in this disclosure one by one.

With the rapid development of the new media industry, a sharp increaseof data volume in the media industry poses a challenge to a networktransmission capability. In particular, emerging media streams such asultra high-definition videos and VR panoramic videos, have higherrequirements on a data delay. As shown in FIG. 5 , a current datatransmission method is implemented by using the TCP protocol. An ASserver sends data to a UPF, the UPF sends the data to a RAN, and thenthe RAN sends the data to UE1 for display. It is assumed that the UE1can feed back a receiving response to the received data, where thereceiving response may represent a TCP sequence number of a receiveddata packet. For example, if the UE1 receives the data packets 1, 2, 3,and 4 sent by the AS, the UE1 may directly return 3 in the receivingresponse to indicate the largest TCP sequence number in the receiveddata, or may return 1, 2, and 3 in the receiving response to indicateall TCP sequence numbers in the received data. However, the TCP protocolhas in-sequence delivery, in other words, when data is sent, there is acorresponding TCP sequence number. Once a piece of data is lost andretransmitted, even if subsequent data reaches a TCP layer of areceiving end, subsequent data is not uploaded to the AS server until asubsequent retransmitted data packet arrives. Therefore, a client (forexample, UE 1) waits during data transmission, and frame freezing duringplay is caused at a media service layer.

Based on the foregoing requirements, an embodiment of this disclosureprovides a communication method that may optimize network transmissionquality, and avoid an extra delay caused by retransmission. It should beunderstood that this embodiment of this disclosure is not onlyapplicable to a communication system in which data is transmittedthrough the TCP protocol, but also applicable to a communication systemwith in-sequence delivery and retransmission reliability. FIG. 6 is anexample flowchart of a communication method shown from a perspective ofdevice interaction, and may include the following steps.

Step 601: A user plane function network element receives first data andsends the first data to an access network network element.

The user plane function network element may receive the first data froman application server, and the first data may be sent from theapplication server to the user plane function network element.

Step 602: The user plane function network element receives second dataand sends the second data to the access network network element.

Similarly, the user plane function network element may receive thesecond data from the application server, and the second data may be sentfrom the application server to the user plane function network element.

Step 603: The user plane function network element determines, based onfirst information, that the second data is retransmitted data of thefirst data.

The first information herein may be information used by the user planefunction network element to determine whether the second data is theretransmitted data of the first data or out-of-order data. The followingseparately describes different cases of the first information.

Case 1: The first information includes a data packet sequence numberdifference threshold.

The first information may be received from the application server. Thedata packet sequence number difference threshold herein may be set basedon an empirical value. This is not specifically limited in thisdisclosure.

In an example, the user plane function network element may determine,based on a difference between a data packet sequence number of thesecond data and a data packet sequence number of adjacent data, and thedata packet sequence number difference threshold, whether the differenceis greater than or equal to the data packet sequence number differencethreshold. If the difference is greater than or equal to the data packetsequence number difference threshold, the user plane function networkelement may determine that the second data is the retransmitted data ofthe first data; or if the difference is not greater than or equal to thedata packet sequence number difference threshold, the user planefunction network element may determine that the second data is not theretransmitted data of the first data.

In another example, the user plane function network element maydetermine, based on a difference between a data packet sequence numberof the second data and a data packet sequence number of adjacent data,and the data packet sequence number difference threshold, whether thesecond data is out-of-order data. For example, if the difference betweenthe data packet sequence number of the second data and the data packetsequence number of the adjacent data is greater than or equal to thedata packet sequence number difference threshold, the second data isout-of-order data. The out-of-order data may be data whose data packetsequence number is far greater than or far less than a data packetsequence number of adjacent data. For example, the user plane functionnetwork element separately receives data packets with sequence numbers2, 18, and 3. It can be learned that the sequence number 18 of the datapacket is far greater than the sequence numbers 2 and 3 of the adjacentdata. Therefore, it may be considered that the data of the data packetsequence number 18 is out-of-order data.

Case 2: The first information includes a receiving response to the firstdata.

The first information herein may be received from the access networknetwork element. After the user plane function network element sends thefirst data to the access network network element, if the access networknetwork element receives the first data, the access network networkelement may send the receiving response to the first data to the userplane function network element. The user plane function network elementmay record the receiving response and the first data corresponding tothe receiving response.

In an example, the user plane function network element may record a datapacket sequence number of the sent first data and a data packet sequencenumber of the first data corresponding to the received receivingresponse. The user plane function network element may determine, basedon the record, whether the receiving response to the first data isreceived.

In another example, the user plane function network element may recorddata packet sequence numbers of the sent first data. If the user planefunction network element receives the receiving response to the firstdata, the user plane function network element may determine the datapacket sequence number of the first data corresponding to the receivingresponse, and delete the data packet sequence number from the recordeddata packet sequence numbers. The user plane function network elementmay determine, based on remaining data packet sequence numbers in therecord, which first data whose receiving responses are not received.

The user plane function network element may identify, based on thereceiving response to the first data, whether the second data is theretransmitted data of the first data. For example, if a data packetsequence number of the second data received by the user plane functionnetwork element is the same as the data packet sequence number of thefirst data, and the first information does not include the receivingresponse to the first data, the user plane function network element maydetermine that the second data is the retransmitted data to the firstdata.

For example, the user plane function network element receives first datawith data packet sequence numbers 1, 2, and 3. The user plane functionnetwork element may separately send the first data with data packetsequence numbers 1, 2, and 3 to the access network network element.After receiving the foregoing three pieces of first data, a terminaluser may send receiving responses to the first data to the user planefunction network element. The user plane function network elementreceives, from the access network network element, receiving responsesto the first data with data packet sequence numbers 1 and 3. The userplane function network element then receives second data with a datapacket sequence number 2, but the first information does not include areceiving response to the first data with the data packet sequencenumber 2. Therefore, the user plane function network element maydetermine that the second data with the data packet sequence number 2 isretransmitted data of the first data with the data packet sequencenumber 2.

Step 604: The user plane function network element may send firstindication information to the access network network element.

The first indication information herein may indicate that the seconddata is the retransmitted data, or indicate a sending priority of thesecond data. For example, when determining that the second data is theretransmitted data, the user plane function network element may send, tothe access network network element, the first indication informationindicating that the second data is the retransmitted data, or send, tothe access network network element, the first indication informationindicating that the sending priority of the second data is highest. Forexample, the first indication information herein may be an identifier,and the identifier may indicate that the second data is theretransmitted data, or indicate the sending priority of the second data.

Optionally, the first indication information may indicate that thesecond data is out-of-order data. In addition, the first indicationinformation may further indicate that, when the second data isout-of-order data, the data packet sequence number of the second data isless than that of adjacent data, or when the second data is out-of-orderdata, the data packet sequence number of the second data is greater thanthat of the adjacent data. In this case, if the data packet sequencenumber of the second data is less than that of the adjacent data, thesecond data needs to be preferentially sent; or if the data packetsequence number of the second data is greater than that of the adjacentdata, the first data needs to be preferentially sent.

In an example, the sending priority of the second data may be indicatedthrough QoS flow identification information. For example, the firstindication information may be identification information of a first QoSflow. In this case, the first data may be sent through a second QoSflow, and the second data may be sent through the first QoS flow. Apriority of the first QoS flow herein is higher than that of the secondQoS flow. The user plane function network element may send the firstindication information to the access network network element, toindicate that a QoS flow of the second data is the first QoS flow. Whenreceiving the identification information of the first QoS flow as thefirst indication information, the access network network element maysend the second data through the first QoS flow, and send the first datathrough the second QoS flow. Specifically, the access network networkelement maps data of different QoS flows to corresponding data radiobearers (Data Radio Bearers, DRBs) and sends the data to a user side.

In addition, it should be noted that the first QoS flow and the secondQoS flow herein are generated by a policy control function networkelement. The policy control function network element may receive secondindication information from the application server. The policy controlfunction network element may generate, based on the second indicationinformation, the first QoS flow and the second QoS flow with differentpriorities. The priority of the first QoS flow may be higher than thatof the second QoS flow. It should be understood that the policy controlfunction network element may generate two QoS flows, three QoS flows, ora plurality of QoS flows. This is not specifically limited in thisdisclosure. A plurality of QoS flows generated by the policy controlfunction network element have different priorities.

In this embodiment of this disclosure, the user plane function networkelement may include the first indication information in a GPRS tunnelingprotocol (GPRS Tunneling Protocol, GTP) layer, which is specifically aGTP-U layer, of a data packet of the second data. The GTP layer is alayer that can be identified by the access network network element.Therefore, the access network network element may identify the firstindication information at the GTP layer.

Optionally, in this embodiment of this disclosure, the access networknetwork element may determine the sending priority of the second databased on the first indication information.

The access network network element may determine, based on theindication information, that the sending priority of the second data ishigher than that of the first data. In this case, the access networknetwork element may perform priority scheduling, and preferentiallytransmit the second data. Alternatively, the access network networkelement may determine, based on the indication information, that thesending priority of the second data is lower than that of the firstdata. In this case, the access network network element may performpriority scheduling, and preferentially transmit the first data.

For example, when the first indication information indicates that thesecond data is the retransmitted data of the first data, the accessnetwork network element may determine that the sending priority of thesecond data is higher than that of the first data, and the accessnetwork network element may perform priority scheduling, andpreferentially transmit the second data.

In an example, the access network network element may determine, basedon the first indication information, that the second data isout-of-order data. In this case, the access network network element maydetermine the sending priority of the second data based on the firstindication information. For example, the first indication informationmay indicate that the second data is out-of-order data, and that thedata packet sequence number of the second data is less than that of theadjacent data. In this case, the access network network element maydetermine that the sending priority of the second data is higher thanthat of the first data. For another example, the first indicationinformation may indicate that the second data is out-of-order data, andthat the data packet sequence number of the second data is greater thanthat of the adjacent data. In this case, the access network networkelement may determine that the sending priority of the second data islower than that of the first data.

In addition, it should be noted that the access network network elementmay receive second information from a session management functionnetwork element, and the second information includes the firstindication information. Therefore, when the access network networkelement determines that the first indication information from thesession management function network element is the same as the firstindication information from the user plane function network element, thesecond data is considered as the retransmitted data or out-of-orderdata. In this case, the access network network element may performpriority scheduling based on the first indication information.

The following describes, with reference to FIG. 7 , a method fortransmitting first data and second data when first information includesa data packet difference threshold. FIG. 7 is an example flowchart of acommunication method shown from a perspective of device interaction, andmay include the following steps.

Step 701: An application server sends indication information to a policycontrol function network element.

For example, the application server sends the indication information tothe policy control function network element through an AF request (AFrequest) message. Optionally, the AF request message may further includea data packet sequence number difference threshold. In this case, thedata packet sequence number may be a TCP sequence number, and the datapacket sequence number difference threshold may be a TCP sequence numberdifference threshold. The indication information may include flowdescription information, and is used by the policy control functionnetwork element to determine that priority scheduling needs to beperformed on a service corresponding to the flow descriptioninformation.

Step 702: A terminal device initiates a protocol data unit (protocoldata unit, PDU) session establishment procedure, and the terminal devicesends a PDU session establishment message to a session managementfunction network element.

Optionally, if the terminal device has established a PDU session withthe session management function network element, the terminal device maysend a PDU Session Modification Request message to the sessionmanagement function network element in step 701 to initiate a PDUsession modification procedure.

Specifically, the UE sends a PDU session establishment/modificationrequest message to an access and mobility management network element,and after selecting the session management function network element, theaccess and mobility management function network element sendssession-related information from the UE to the session managementfunction network element through aNsmf_PDUSession_CreateSMContext/UpdateSMContext service.

Step 703: The session management function network element initiatessession management policy association establishment to the policycontrol function network element.

Optionally, if the procedure initiated by the terminal device in step702 is a PDU session modification procedure, in step 703, the sessionmanagement function network element may initiate a session managementpolicy association modification procedure to the policy control functionnetwork element.

Optionally, in a session management policy associationestablishment/modification procedure, the policy control functionnetwork element sends the difference threshold and first indicationinformation to the session management function network element.

Step 704: The session management function network element sends the datapacket sequence number difference threshold and the first indicationinformation to the user plane function network element.

The first indication information herein may be indication informationindicating that the second data is retransmitted data of the first data,or may be indication information indicating a sending priority of thesecond data.

Step 705: The session management function network element includes thefirst indication information in N2 SM information and sends the N2 SMinformation to an access network network element through the access andmobility management function network element.

Specifically, the session management function network element sends theN2 SM information to a mobility management function network element sidethrough a Namf_Communication_N1N2MessageTransfer service, and a mobilitymanagement function network element notifies an access network networkelement side in an N2 PDU Session procedure. Optionally, the sessionmanagement function network element may alternatively include secondindication information in the N2 SM information.

Step 706: Complete a remaining part of the PDU session establishmentprocedure.

Alternatively, the PDU session modification procedure may be completedin step 706.

Step 707: The user plane function network element determines adifference between a data packet sequence number of the second data anda data packet sequence number of adjacent data.

If the user plane function network element determines that thedifference between the data packet sequence number of the second dataand the data packet sequence number of the adjacent data exceeds thedata packet sequence number difference threshold, the second data may beconsidered as the retransmitted data or out-of-order data.

Step 708: The user plane function network element sends a retransmitteddata packet or an out-of-order data packet that includes the firstindication information to the access network network element.

The user plane function network element may include the first indicationinformation in a GTP layer of a data packet of the second data, and sendthe data packet to the access network network element. The firstindication information herein may indicate that the second data is theretransmitted data or out-of-order data, or indicate the priority of thesecond data.

Step 709: The access network network element performs priorityscheduling based on the first indication information.

For a specific manner in which the access network network elementperforms priority scheduling based on the first indication information,refer to the descriptions in the method embodiment shown in FIG. 6 .Details are not described herein again.

The following describes, with reference to FIG. 8 , a method fortransmitting first data and second data when first information includesa receiving response to the first data. FIG. 8 is an example flowchartof a communication method shown from a perspective of deviceinteraction, and may include the following steps.

Step 801: An application server sends first indication information to apolicy control function network element through an AF request message.

Optionally, the indication information may include flow descriptioninformation, and is used by the policy control function network elementto determine that priority scheduling needs to be performed on a servicecorresponding to the flow description information.

Step 802: A terminal device initiates a PDU session establishmentprocedure, and the terminal device sends a PDU session establishmentmessage to a session management function network element.

Optionally, if the terminal device has established a PDU session withthe session management function network element, the terminal device maysend a PDU Session Modification Request message to the sessionmanagement function network element in step 801 to initiate a PDUsession modification procedure.

Specifically, the UE sends a PDU session establishment/modificationrequest message to an access and mobility management network element,and after selecting the session management function network element, theaccess and mobility management function network element sendssession-related information from the UE to the session managementfunction network element through aNsmf_PDUSession_CreateSMContext/UpdateSMContext service.

Step 803: The session management function network element initiatessession management policy association establishment to the policycontrol function network element.

Optionally, if the procedure initiated by the terminal device in step802 is a PDU session modification procedure, in step 803, the sessionmanagement function network element may initiate a session managementpolicy association modification procedure to the policy control functionnetwork element.

Optionally, in a session management policy associationestablishment/modification procedure, the policy control functionnetwork element sends the first indication information to the sessionmanagement function network element.

Step 804: The session management function network element sends firstindication information to the user plane function network element.

The first indication information herein may be indication informationindicating that the second data is retransmitted data of the first data,or may be indication information indicating a sending priority of thesecond data.

Step 805: The session management function network element includes thefirst indication information in N2 SM information and sends the N2 SMinformation to an access network network element through the access andmobility management function network element.

Specifically, the session management function network element sends theN2 SM information to a mobility management function network element sidethrough a

Namf_Communication_N1N2MessageTransfer service, and a mobilitymanagement function network element notifies an access network networkelement side in an N2 PDU Session procedure. Optionally, the sessionmanagement function network element may alternatively include secondindication information in the N2 SM information.

Step 806: Complete a remaining part of the PDU session establishmentprocedure.

Alternatively, the PDU session modification procedure may be completedin step 806.

Step 807: The user plane function network element records data packetsequence numbers of the first data sent by the application server.

Step 808: The user plane function network element receives a receivingresponse to the first data, and deletes, from the record, the datapacket sequence number of the first data corresponding to the receivingresponse.

Optionally, the user plane function network element may detect anacknowledgment character (acknowledge character, ACK) sequence number ofa data packet header included in uplink data. Specifically, the TCPprotocol is used as an example, and a TCP header message includes theACK sequence number. The ACK sequence number may indicate that a datapacket of the sent first data has been received.

Step 809: If the user plane function network element determines that adata packet sequence number of the second data has been stored in therecord, the user plane function network element sends, to the accessnetwork network element, the second data that includes the firstindication information.

Optionally, the user plane function network element may include thefirst indication information in a GTP layer of a data packet of thesecond data, and send the data packet to the access network networkelement.

Step 810: The access network network element performs priorityscheduling based on the first indication information.

For a specific manner in which the access network network elementperforms priority scheduling based on the first indication information,refer to the descriptions in the method embodiment shown in FIG. 6 .Details are not described herein again.

The following describes, with reference to FIG. 9A and FIG. 9B, a methodfor transmitting first data and second data through QoS flows withdifferent priorities. FIG. 9A and FIG. 9B are an example flowchart of acommunication method shown from a perspective of device interaction, andmay include the following steps.

Step 901: An application server sends indication information to a policycontrol function network element through an AF request message.

An AF may send the information to the PCF through an NEF and the AFsends the information to the NEF through anNnef_ServiceParameter_Create/Update service. Then, the NEF stores,updates, or deletes content in a UDR to trigger an Nudr_DM_Notifyservice. In this way, the PCF is notified, and interaction between theAF and the PCF is completed.

Optionally, the AF request message herein may further include a datapacket sequence number difference threshold. A data packet sequencenumber may be a TCP sequence number, and the data packet sequence numberdifference threshold may be a TCP sequence number difference threshold.The indication information may be used to trigger the policy controlfunction network element to generate QoS flows of different priorities.The AF request message may further include flow description information,and the flow description information herein may be used by the policycontrol function network element to determine a specific service of theQoS flow that needs to be generated.

Step 902: A terminal device initiates a PDU session establishmentprocedure, and the terminal device sends a PDU session establishmentmessage to a session management function network element.

Optionally, if the terminal device has established a PDU session, theterminal device may send a PDU Session Modification Request message tothe session management function network element in step 902 to initiatea PDU session modification procedure.

Specifically, the UE sends a PDU session establishment/modificationrequest message to an access and mobility management network element,and after selecting the session management function network element, theaccess and mobility management function network element sendssession-related information from the UE to the session managementfunction network element through aNsmf_PDUSession_CreateSMContext/UpdateSMContext service.

Step 903: The session management function network element initiatessession management policy association establishment to the policycontrol function network element.

Optionally, if the procedure initiated by the terminal device in step902 is the PDU session modification procedure, in step 903, the sessionmanagement function network element may initiate a session managementpolicy association modification procedure to the policy control functionnetwork element.

Step 904: The policy control function network element generates, basedon the indication information, a first PDU session-related policycorresponding to a first QoS flow and a second PDU session-relatedpolicy corresponding to a second QoS flow.

A priority of the first QoS flow herein may be higher than that of thesecond QoS flow.

Step 905: The policy control function network element sends policyinformation of the first QoS flow and policy information of the secondQoS flow to the session management function network element.

The policy information may indicate that the priority of the first QoSflow is higher than that of the second QoS flow. Optionally, the policycontrol function network element may send the first PDU session-relatedpolicy, the second PDU session-related policy, and the data packetsequence number difference threshold to the session management functionnetwork element.

Step 906: The session management function network element generatesrelated information of the first QoS flow and the second QoS flow basedon the policy information, where the related information includes aspecific QoS parameter and a QoS flow identifier QFI.

Step 907 and step 908 may be the same as step 704 and step 705 shown inFIG. 7 , or step 907 and step 908 may be the same as step 804 and step805 shown in FIG. 8 .

Step 909: The user plane function network element determines that thesecond data is retransmitted data of the first data.

In step 909, the user plane function network element may determine,based on step 705 shown in FIG. 7 or step 805 to step 807 shown in FIG.8 , that the second data is the retransmitted data of the first data.

Step 910: The user plane function network element maps the second datato the first QoS flow, and maps the first data to the second QoS flow.

Step 911: The access network network element sends the second data inthe first QoS flow to the terminal device through a data radio bearer(Data Radio Bearer, DRB) corresponding to the first QoS flow, and sendsthe first data in the second QoS flow to the terminal device through aDRB corresponding to the second QoS flow.

This embodiment of this disclosure further provides anothercommunication method. FIG. 10 is an example flowchart of a communicationmethod shown from a perspective of device interaction, and may includethe following steps.

Step 1001: An application server sends first data to an access networknetwork element through a user plane function network element.

The first data herein includes first indication information, and thefirst indication information may indicate a sending sequence of datapackets of the first data at an application server end. The firstindication information may be a data packet sequence number, or may beidentification information for identifying a data packet sequencenumber. For example, the first indication information may be a TCPsequence number, or may be identification information that identifies adata sending sequence of the application server.

Optionally, the user plane function network element may add the firstindication information to a GTP layer of the first data and send thefirst data to the access network network element. Alternatively, theuser plane function network element may map the first indicationinformation to new indication information and add the new indicationinformation to a GTP layer of the first data.

Step 1002: The access network network element determines a sendingpriority of the first data based on the first indication information orthe new indication information included in the first data.

The access network network element may determine the priority of thefirst data based on the sending sequence of the data packets of thefirst data at the application server end. For example, first data sentby the application server side first has a higher priority, and firstdata sent later has a lower priority.

In an example, the priority of the first data may be determined based onthe data packet sequence number identified by the first indicationinformation, and a smaller data packet sequence number indicates ahigher priority of the first data. Therefore, the access network networkelement may send the first data in ascending order of data packetsequence numbers. High-priority processing may be performed on datawhose data packet sequence number is far less than a data packetsequence number of adjacent data, and low-priority processing may beperformed on data whose data packet sequence number is far greater thana data packet sequence number of adjacent data.

For example, the access network network element separately receivesfirst data with data packet sequence numbers 2, 3, 4, 19, 22, 6, and 8,and the access network network element may preferentially send the firstdata with the data packet sequence numbers 2, 3, 4, 6, and 8. However,the first data with the data packet sequence numbers 19 and 22 herein isout-of-order data, and the data packet sequence numbers are far lessthan the data packet sequence numbers of the adjacent data. Therefore,sending of such data may be delayed.

In addition, it should be noted that the access network network elementmay receive second indication information from a session managementfunction network element. The second indication information herein mayindicate the access network network element to transmit data based ontransmission priority information. After receiving the second indicationinformation, the access network network element may perform priorityscheduling based on the first indication information.

The following describes, with reference to FIG. 11 , a data transmissionmethod when first indication information indicates a sending sequence ofdata packets of first data at an application server end. FIG. 11 is anexample flowchart of a communication method shown from a perspective ofdevice interaction, and may include the following steps.

Step 1101: An application server sends indication information to apolicy control function network element through an AF request message.

Optionally, the AF request message herein may further includeidentification information of a data packet sequence number. Theidentification information may be an identifier of the data packetsequence number, or may be a mapping of the identifier of the datapacket sequence number. The indication information may include flowdescription information, and is used by the policy control functionnetwork element to determine that priority scheduling needs to beperformed on a service corresponding to the flow descriptioninformation.

Step 1102: A terminal device initiates a PDU session establishmentprocedure, and the terminal device sends a PDU session establishmentmessage to a session management function network element.

Optionally, if the terminal device has established a PDU session withthe session management function network element, the terminal device maysend a modification request message to the session management functionnetwork element in step 1101 to initiate a PDU session modificationprocedure.

Step 1103: The session management function network element initiatessession management policy association establishment to the policycontrol function network element.

Optionally, if the procedure initiated by the terminal device in step1101 is a PDU session modification procedure, in step 1102, the sessionmanagement function network element may initiate a session managementpolicy modification procedure to the policy control function networkelement.

Step 1104: The session management function network element sends secondindication information to an access network network element through anaccess and mobility management function network element.

The second indication information herein may indicate the access networknetwork element to transmit data based on priority information.Optionally, the session management function network element may send theidentification information of the data packet sequence number to theaccess network network element and a user plane function networkelement, so that the user plane function network element and the accessnetwork network element may transmit first data based on theidentification information.

Step 1105: Complete a remaining part of the PDU session establishmentprocedure.

Alternatively, the PDU session modification procedure may be completedin step 1104.

Step 1106: The user plane function network element includes the datapacket sequence number or the identification information of the datapacket sequence number in the first data, and sends the first data tothe access network network element.

In this case, the user plane function network element may include thedata packet sequence number or the identification information of thedata packet sequence number in a GTP layer of the first data, and sendthe first data to the access network network element.

Step 1107: The access network network element performs priorityscheduling based on the data packet sequence number or theidentification information of the data packet sequence number.

The access network network element may send the first data in ascendingorder of data packet sequence numbers or in ascending order of datapacket sequence numbers identified by the identification information. Ifa data packet sequence number of one piece of first data is less than adata packet sequence number of adjacent data, and a difference betweenthe two exceeds a preset difference threshold, high-priority processingmay be performed on the first data, in other words, the first data maybe sent preferentially. If a data packet sequence number of one piece offirst data is greater than a data packet sequence number of adjacentdata, and a difference between the two exceeds a preset differencethreshold, low-priority processing may be performed on the first data,in other words, sending of the first data may be delayed.

Based on a same technical concept as the foregoing communication method,as shown in FIG. 10 , an apparatus 1200 with a communication function isprovided. The apparatus 1200 can perform steps performed by the userplane function network element, the access network network element, thepolicy control function network element, or the application server inthe foregoing methods. To avoid repetition, details are not describedherein again. The apparatus 1200 includes: a communication unit 1210, aprocessing unit 1220, and optionally, further includes a storage unit1230. The processing unit 1220 may be connected to the storage unit 1230and the communication unit 1210, and the storage unit 1230 may also beconnected to the communication unit 1210. The processing unit 1220 maybe integrated with the storage unit 1230.

The storage unit 1230 is configured to store a computer program.

For example, when the apparatus 1200 performs the steps performed by theuser plane function network element, the communication unit 1210 isconfigured to receive first data; and the communication unit 1210 isfurther configured to receive second data. The processing unit 1220 isconfigured to determine, based on first information, that the seconddata is retransmitted data of the first data. The communication unit1210 is further configured to send first indication information to theaccess network network element. For descriptions of the first data, thesecond data, and the first indication information, refer to relateddescriptions in the method embodiments shown in FIG. 6 to FIG. 11 .

In a design, the communication unit 1210 is further configured toreceive the first information from the application server, where thefirst information includes a data packet sequence number differencethreshold.

In a design, the processing unit 1220 is specifically configured todetermine that a difference between a data packet sequence number of thesecond data and a data packet sequence number of adjacent data exceedsthe data packet sequence number difference threshold.

In a design, the communication unit is further configured to receive thefirst information from the access network network element, where thefirst information indicates a receiving response to the first data.

In a design, when determining, based on the first information, that thesecond information is the retransmitted data of the first data, theprocessing unit 1220 is specifically configured to: determine that thefirst information does not include the receiving response to the firstdata.

For example, when the apparatus 1200 performs the steps performed by theaccess network network element, the communication unit 1210 isconfigured to receive first data; and the communication unit 1210 isfurther configured to receive second data. The communication unit 1210is further configured to receive indication information from the userplane function network element; and the processing unit 1220 isconfigured to determine a sending priority of the second data based onthe indication information. For descriptions of the first data, thesecond data, and the indication information, refer to relateddescriptions in the method embodiments shown in FIG. 6 to FIG. 11 .Details are not described herein again.

In a design, when determining the sending priority of the second databased on the indication information, the processing unit 1220 isspecifically configured to: determine, based on the indicationinformation, that the sending priority of the second data is higher thanthat of the first data.

In a design, the communication unit 1210 is further configured to sendfirst information to the user plane function network element, where thefirst information indicates a receiving response to the first data. Fordescriptions of the first information, refer to related descriptions inthe method embodiments shown in FIG. 6 to FIG. 11 .

In a design, the communication unit 1210 is further configured toreceive second information from a session management function networkelement, where the second information includes the indicationinformation. For descriptions of the second information, refer torelated descriptions in the method embodiments shown in FIG. 6 to FIG.11 .

For example, when the apparatus 1200 performs steps performed by thepolicy control function network element, the communication unit 1210 isconfigured to receive indication information from the applicationserver; and the processing unit 1220 is configured to generate a firstquality of service QoS flow and a second QoS flow based on theindication information. The communication unit 1210 is furtherconfigured to send policy information of the first QoS flow and policyinformation of the second QoS flow to the session management functionnetwork element. For descriptions of the indication information, thefirst QoS flow, the second QoS flow, and the policy information, referto related descriptions shown in FIG. 6 to FIG. 11 .

For example, when the apparatus 1200 performs steps performed by theaccess network network element, the communication unit 1210 isconfigured to receive first data, where the first data includes firstindication information; and the processing unit 1220 is configured todetermine a sending priority of the first data based on the firstindication information. For descriptions of the first data and the firstindication information, refer to related descriptions in the methodembodiments shown in FIG. 6 to FIG. 11 .

In a design, the communication unit 1210 is further configured toreceive second indication information from the session managementfunction network element. For descriptions of the second indicationinformation, refer to related descriptions in the method embodimentsshown in FIG. 6 to FIG. 11 .

For example, when the apparatus 1200 performs steps performed by theapplication server, the processing unit 1220 is configured to send firstdata to the access network network element by using the communicationunit 1210 through the user plane function network element, where thefirst data includes first indication information, and the firstindication information indicates a sending sequence of data packets ofthe first data in the apparatus. For descriptions of the first data andthe first indication information, refer to related descriptions in themethod embodiments shown in FIG. 6 to FIG. 11 . Details are notdescribed herein again.

Alternatively, the foregoing apparatus may be a chip. The communicationunit may be an input/output circuit or an interface of the chip. Theprocessing unit may be a logic circuit, and the logic circuit mayprocess to-be-processed data according to the steps described in theforegoing methods, to obtain processed data. The outputcircuit/interface is configured to output the processed data.

FIG. 13 shows an apparatus 1300 with a communication function accordingto an embodiment of this disclosure. The apparatus 1300 is configured toimplement functions of the user plane function network element, theaccess network network element, the policy control function networkelement, and the application server in the foregoing methods. Theapparatus 1300 may be the user plane function network element, theaccess network network element, the policy control function networkelement, and the application server, or may be a chip similar to theuser plane function network element, the access network network element,the policy control function network element, and the application server,or may be an apparatus that can be used with the user plane functionnetwork element, the access network network element, the policy controlfunction network element, and the application server for matching.

The apparatus 1300 includes at least one processor 1320, configured toimplement functions of the user plane function network element, theaccess network network element, the policy control function networkelement, and the application server in the methods provided inembodiments of this disclosure. The apparatus 1300 may further include acommunication interface 1310. In embodiments of this disclosure, thecommunication interface may be a transceiver, a circuit, a bus, amodule, or a communication interface of another type, and is configuredto communicate with another device through a transmission medium. Forexample, the communication interface 1310 is used by an apparatus in theapparatus 1300 to communicate with another device. The processor 1320may implement a function of the processing unit 1220 shown in FIG. 12 ,and the communication interface 1310 may implement a function of thecommunication unit 1210 shown in FIG. 12 .

The apparatus 1300 may further include at least one memory 1330,configured to store program instructions and/or data. The memory 1330 iscoupled to the processor 1320. The coupling in this embodiment of thisdisclosure may be an indirect coupling or a communication connectionbetween apparatuses, units, or modules in an electrical form, amechanical form, or another form, and is used for information exchangebetween the apparatuses, the units, or the modules. The processor 1320may operate in collaboration with the memory 1330. The processor 1320may execute the program instructions stored in the memory 1330. At leastone of the at least one memory may be included in the processor.

In this embodiment of this disclosure, a specific connection mediumbetween the communication interface 1310, the processor 1320, and thememory 1330 is not limited. In this embodiment of this disclosure, thememory 1330, the processor 1320, and the communication interface 1310are connected through a bus 1340 in FIG. 13 . The bus is represented bya bold line in FIG. 13 . A connection manner between other components ismerely an example for description, and is not limited thereto. The busmay be classified into an address bus, a data bus, a control bus, andthe like. For ease of representation, only one bold line is used torepresent the bus in FIG. 13 , but this does not mean that there is onlyone bus or only one type of bus.

In another form of this embodiment, a computer-readable storage mediumis provided, and the storage medium stores instructions. When theinstructions are executed, a method on a user plane function networkelement side, an access network network element side, a policy controlfunction network element side, or an application server side in theforegoing method embodiments is performed.

In another form of this embodiment, a computer program product includinginstructions is provided. When the instructions are executed, a methodon a user plane function network element side, an access network networkelement side, a policy control function network element side, or anapplication server side in the foregoing method embodiments isperformed.

In another form of this embodiment, a communication system is provided,and the system may include the foregoing at least one first user planefunction network element, at least one access network network element,at least one policy control function network element, and at least oneapplication server.

It should be understood that the processor mentioned in embodiments ofthe present disclosure may be a central processing unit (CentralProcessing Unit, CPU), or may be another general-purpose processor, adigital signal processor (Digital Signal Processor, DSP), anapplication-specific integrated circuit (Application-Specific IntegratedCircuit, ASIC), a field programmable gate array (Field Programmable GateArray, FPGA) or another programmable logic device, a discrete gate ortransistor logic device, a discrete hardware component, or the like. Thegeneral-purpose processor may be a microprocessor, or the processor maybe any conventional processor or the like.

It should be further understood that the memory mentioned in embodimentsof the present disclosure may be a volatile memory or a nonvolatilememory, or may include a volatile memory and a nonvolatile memory. Thenonvolatile memory may be a read-only memory (Read-Only Memory, ROM), aprogrammable read-only memory (Programmable ROM, PROM), an erasableprogrammable read-only memory (Erasable PROM, EPROM), an electricallyerasable programmable read-only memory (Electrically EPROM, EEPROM), ora flash memory. The volatile memory may be a random access memory(Random Access Memory, RAM), used as an external cache. Through examplebut not limitative descriptions, many forms of RAMs may be used, forexample, a static random access memory (Static RAM, SRAM), a dynamicrandom access memory (Dynamic RAM, DRAM), a synchronous dynamic randomaccess memory (Synchronous DRAM, SDRAM), a double data rate synchronousdynamic random access memory (Double Data Rate SDRAM, DDR SDRAM), anenhanced synchronous dynamic random access memory (Enhanced SDRAM,ESDRAM), a synchlink dynamic random access memory (Synchlink DRAM,SLDRAM), and a direct rambus random access memory (Direct Rambus RAM, DRRAM).

It should be noted that when the processor is a general purposeprocessor, a DSP, an ASIC, an FPGA or another programmable logic device,a discrete gate, a transistor logic device, or a discrete hardwarecomponent, the memory (a storage module) is integrated into theprocessor.

It should be noted that the memory described in this specification aimsto include but is not limited to these memories and any memory ofanother proper type.

It should be understood that sequence numbers of the foregoing processesdo not mean execution sequences in various embodiments of thisdisclosure. The execution sequences of the processes should bedetermined based on functions and internal logic of the processes, andshould not be construed as any limitation on an implementation processesof embodiments of the present disclosure.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraint conditions ofthe technical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of this disclosure.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatuses, and units, refer to acorresponding process in the foregoing method embodiments. Details arenot described herein again.

In the several embodiments provided in this disclosure, it should beunderstood that the disclosed system, apparatuses, and methods may beimplemented in other manners. For example, the described apparatusembodiments are merely examples. For example, division into the units ismerely logical function division and may be other division during actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of embodiments.

In addition, functional units in embodiments of this disclosure may beintegrated into one processing unit, each of the units may exist alonephysically, or two or more units are integrated into one unit.

When the functions are implemented in the form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of this disclosure essentially,or the part contributing to a current technology, or some of thetechnical solutions may be implemented in a form of a software product.The computer software product is stored in a storage medium, andincludes several instructions for instructing a computer device (whichmay be a personal computer, a server, a network device, or the like) toperform all or some of the steps of the methods described in embodimentsof this disclosure. The foregoing storage medium includes any mediumthat can store program code, such as a USB flash drive, a removable harddisk, a read-only memory (Read-Only Memory, ROM), a random access memory(Random Access Memory, RAM), a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementations of thisdisclosure, but are not intended to limit the protection scope of thisdisclosure. Any variation or replacement readily figured out by a personskilled in the art within the technical scope disclosed in thisdisclosure shall fall within the protection scope of this disclosure.Therefore, the protection scope of this disclosure shall be subject tothe protection scope of the claims.

What is claimed is:
 1. A communication method, comprising: receiving, bya user plane function network element, second data; determining, by theuser plane function network element based on first information, that thesecond data is retransmitted data of first data, wherein both the firstdata and the second data are data sent by an application server to auser side; and sending, by the user plane function network element,first indication information to an access network network element,wherein the first indication information indicates that the second datais the retransmitted data, or the first indication information indicatesa sending priority of the second data.
 2. The method according to claim1, further comprising: receiving, by the user plane function networkelement, the first information from the application server, wherein thefirst information comprises a data packet sequence number differencethreshold.
 3. The method according to claim 2, wherein determining, bythe user plane function network element based on the first information,that the second data is the retransmitted data of the first datacomprises: determining, by the user plane function network element, thata difference between a data packet sequence number of the second dataand a data packet sequence number of adjacent data exceeds the datapacket sequence number difference threshold.
 4. The method according toclaim 1, further comprising: receiving, by the user plane functionnetwork element, the first information from the access network networkelement, wherein the first information indicates a receiving response tothe first data.
 5. The method according to claim 4, wherein determining,by the user plane function network element based on first information,that the second data is the retransmitted data of the first datacomprises: determining, by the user plane function network element, thatthe first information does not comprise the receiving response to thefirst data.
 6. The method according to claim 1, wherein the firstindication information is identification information of a first qualityof service (QoS) flow, the first data is sent through a second QoS flow,and a priority of the first QoS flow is higher than that of the secondQoS flow.
 7. A communication method, comprising: receiving, by an accessnetwork network element, second data; receiving, by the access networknetwork element, first indication information from a user plane functionnetwork element, wherein the first indication information indicates thatthe second data is retransmitted data of first data, or indicates asending priority of the second data, and both the first data and thesecond data are data sent by an application server to a user side; anddetermining, by the access network network element, the sending priorityof the second data based on the first indication information.
 8. Themethod according to claim 7, wherein determining, by the access networknetwork element, the sending priority of the second data based on thefirst indication information comprises: determining, by the accessnetwork network element based on the first indication information, thatthe sending priority of the second data is higher than that of the firstdata.
 9. The method according to claim 7, further comprising: sending,by the access network network element to the user plane function networkelement, first information indicating a receiving response to the firstdata.
 10. The method according to claim 7, further comprising:receiving, by the access network network element from a sessionmanagement function network element, second information comprising thefirst indication information.
 11. The method according to claim 7,wherein the first indication information is identification informationof a first quality of service (QoS) flow, the first data is sent througha second QoS flow, and a priority of the first QoS flow is higher thanthat of the second QoS flow.
 13. A communication apparatus, a processor,and a memory coupled to the processor and configured to store a computerprogram, the computer program comprising instructions that, whenexecuted by the processor, cause the communication apparatus to performthe following: receiving second data; determining, based on firstinformation, that the second data is retransmitted data of first data,wherein both the first data and the second data are data sent by anapplication server to a user side; and sending first indicationinformation to an access network network element, wherein the firstindication information indicates that the second data is theretransmitted data, or the first indication information indicates asending priority of the second data.
 14. The apparatus according toclaim 13, the computer program further comprising instructions that,when executed by the processor, cause the communication apparatus toperform the following: receiving the first information from theapplication server, wherein the first information comprises a datapacket sequence number difference threshold.
 15. The apparatus accordingto claim 14, wherein determining, based on the first information, thatthe second data is the retransmitted data of the first data comprises:determining that a difference between a data packet sequence number ofthe second data and a data packet sequence number of adjacent dataexceeds the data packet sequence number difference threshold.
 16. Acommunication apparatus, a processor, and a memory coupled to theprocessor and configured to store a computer program, the computerprogram comprising instructions that, when executed by the processor,cause the communication apparatus to perform the following: receivingsecond data; receiving first indication information from a user planefunction network element, wherein the first indication informationindicates that the second data is retransmitted data of first data, orindicates a sending priority of the second data, and both the first dataand the second data are data sent by an application server to a userside; and determining the sending priority of the second data based onthe first indication information.
 17. The apparatus according to claim16, wherein determining the sending priority of the second data based onthe first indication information comprises: determining, based on thefirst indication information, that the sending priority of the seconddata is higher than that of the first data.